First visit? Check out our HELP page for info on how to use this Forum.
Visitors are welcome to read posts, but must REGISTER to make posts.
For a step-by-step guide on how to register, CLICK HERE
To view posts, choose a subforum from the selection below.

Cleaned filters

01-01-2019, 07:54 AM

I though New Years would be a good time to clean the filter on my Oneida,omg it was heavily caked,took a lot of effort to get it decent,but what a differance in performance.i have tried to clean it twice a year,but can't say I've been diligent. Also,I'd did a run of mdf doors in the summer,so wondering if more dust makes it to the filter with mdf. I don't have a method of measuring performance,I do wonder how often others clean filters.
i have found that oneida' s method of low pressure air blown from the outside doesn't really work well,perhaps if I did that weekly?
Edit,I am also have wondered how much effect over filling the drum has on plugging the filter, and on that note how full is too full?

Re: Cleaned filters

01-01-2019, 07:56 PM

Al,

These cyclones are designed to achieve a certain level of mechanical particle separation from the air stream in 2 stages.
Stage 1. Cyclone. The dirty air comes in, spins like crazy forcing the dirt to the outside, down the sides into a dead air space - the waste bin.
The dirt that does not separate, goes to the filters or outside if you can do it. If you can vent outside, you have a single stage on steroids.
Because a properly designed cyclone does such a great job of of separation, we can pass a whole bunch of significantly cleaner air on to Stage 2 - the filters and back into the shop.

The amount of cleaner air coming to the filters is a very difficult specification to find from the manufacturers.
Bill Pentz talks about 99.9% of 30 micron and larger being a general level of efficiency for even trash can separators. So we would all want to see a significant improvement for the money spent.

Bill Pentz claims: Clear Vue Cyclones sells cyclones that use my scalable improved cyclone design which is on these web pages. Our tests of my design were also independently done by four different university medical schools. All results came out near identical. That testing showed my cyclone without filters separates 99% of the total weight of all particles sized 30-microns and larger. To this my cyclone design also separates 99% of all particles sized down to under 5-microns, over half of the weight of even finer particles plus over 88% of the odd shaped particles that go right through traditional cyclone designs. The bottom line is my design sold by Clear Vue consistently tested with its dust bin holding over 97.3% of the weight of the dust produced. My cyclone design only puts about one eight as much of these odd shaped pieces into the filters. Where my cyclone design excels is it it consistently separates off most of the airborne dust. Instead of putting at least 17% of the dust by weight into the filters, my design tested consistently at only putting under 1.6% of the overall dust by weight into the filters.
(http://www.billpentz.com/Woodworking...onereviews.cfm)

If you can accept this as nothing more than a benchmark, then the designs we see today are built to accept only a calculated amount of dirty air carried over to the filters. Every cyclone should have a published separation without filters value. If you are constantly working with MDF, then a 1% decrease in pre-filter separation efficiency is going to mean more frequent filter maintenance.

The amount of cleaner air coming to the filters is a very difficult specification to find from the manufacturers.

Protecting the dead air zone line is very important.
If the bin is full, there is no place for the dirt to leave the air stream. As the cyclone body fills, more and more dirt is carried over into the filters. The more plugged the filters get, performance declines, less separation efficiency. The heavy particles stay in the cyclone body, but more and more particles begin to carry over to the filter.

All of the things that make a cyclone great (great air flow, great particle separation) when operating properly, can backfire and make a real mess of your filters when the process is not working properly.

So, any overflow is to much. The crap you are cleaning out is the stuff you can see ~40 micron and up. Once you are done your cleaning, how much 39 micron and smaller is left behind still plugging the element? I don't know, but likely enough to impede maximum air flow. Once you get them visually clean, the air blowing may work better. There are companies who specialize in filter cleaning, which may be an option.

Once you get your bin management practices under control, you may be looking at replacing your filters. If you have the Oneida "HEPA" class elements, they should hold on to the the dust better than non-HEPA, because that is what true HEPA elements are designed to do.

Kind of long winded, but maybe helps.

Don

Comment

Re: Cleaned filters

01-01-2019, 08:02 PM

You're right, blowing from the outside does little to remove the layers of caked on dust. I blow from the inside at a shallow angle & the dust cake breaks off & blows out the other end of the filter. When the bulk of dust is out of the inside, then I blow it out from the outside. The process still takes a good half out to get it good & clean.

It amazes me how tightly the dust packs into the pleats. MDF dust seems about the worst for getting past the cyclone & packing in the filter.

Comment

Re: Cleaned filters

01-02-2019, 05:35 AM

In the new year,I am going to try to get into the habit of checking the drum every time I enter the shop. Keeping a eye on its level has been a weak point ant too often it has filled into the flex tube.i am going to try blowing into the filter from the outside ,basically the prescribed cleaning method any time I spend a significant amount of time using the dust collector.

Comment

Re: Cleaned filters

In the new year,I am going to try to get into the habit of checking the drum every time I enter the shop. Keeping a eye on its level has been a weak point ant too often it has filled into the flex tube.i am going to try blowing into the filter from the outside ,basically the prescribed cleaning method any time I spend a significant amount of time using the dust collector.

When I read that "cleaning method" I assumed it was daily maintenance. Like you found out, there's no way that a bit of air was going to dislodge caked/packed in dust, unless it was full blast which I feel would damage the filter. So unless it's a daily shot of air, I can't imagine it's to effective.

I was lucky, the filter I got 2 years ago has a metal cage around it, it it can take some light "palm strikes" to the outside to loosen the dust for the few clean outs I perform each year.

Comment

Re: Cleaned filters

01-02-2019, 09:11 AM

I run my shop full time, so ymmv, but part of my morning "open up the shop" routine is to blow the filter on my clearvue with compressed air. I hit it from the outside, up and down and side to side, for about 30 seconds or so, every day. The filter clean out at the bottom is made of clear plexy glass, so when I spray it, I can see the dust falling down into the clean out. Usually there's a good hand ful or so every day. On Fridays I add to the routine - I empty the clean out. There's usually enough fine dust in there to fill my little dustpan, the dust is soft and fine, feels like baby powder.

Mattmatt stopped by last year right after I set this DC up, and had a nifty home made water doodad that allowed us to measure how much power the unit had. I could make a similar doodad pretty easily and test it again, now, to see if I've had a drop in performance over the year.

Matt mentioned at the time though that he's seen people install these doodads permanently on the wall by their DC, so that they have a constant measure of it's performance. When the performance drops, they know their filter is probably clogged. I thought that was a good idea, I'd like to do that some day.

Comment

Re: Cleaned filters

I run my shop full time, so ymmv, but part of my morning "open up the shop" routine is to blow the filter on my clearvue with compressed air. I hit it from the outside, up and down and side to side, for about 30 seconds or so, every day. The filter clean out at the bottom is made of clear plexy glass, so when I spray it, I can see the dust falling down into the clean out. Usually there's a good hand ful or so every day. On Fridays I add to the routine - I empty the clean out. There's usually enough fine dust in there to fill my little dustpan, the dust is soft and fine, feels like baby powder.

Mattmatt stopped by last year right after I set this DC up, and had a nifty home made water doodad that allowed us to measure how much power the unit had. I could make a similar doodad pretty easily and test it again, now, to see if I've had a drop in performance over the year.

Matt mentioned at the time though that he's seen people install these doodads permanently on the wall by their DC, so that they have a constant measure of it's performance. When the performance drops, they know their filter is probably clogged. I thought that was a good idea, I'd like to do that some day.

Maybe Matt will drop by this thread and post a picture of his doodad.

Wow, that last line could really be misinterpreted!

Ryan,
Congratulations on what I would call a "best practice" that everyone should follow, especially heavy users. You have probably noticed that the oldest dust in your waste bin is very much compacted compared to the newest. The same happens in the depths of the filter element pleats. Shop vac elements are a perfect example of this.
When you rely on the "doodad", you accept less than optimal performance.
The only improvement I would recommend is to do the maintenance at the end of each shift so you are ready to go for the next shift.

We noticed that you are using an Ad Blocker.

Would you please consider ‘whitelisting’ forum.canadianwoodworking.com.
The ads make it possible for us to continue hosting our site. For more information on how these ads help us, and to learn how to whitelist our site, please click here.